Sweet Corn Soup vs Tom Yum: the differences

Columnist Vir Sanghvi

What soup do you order when you go to a Chinese restaurant? And what do you order at a Thai restaurant? Don’t think too hard about this one because I suspect I already know the answer. Something like 90 per cent of all Indians order some variation of sweet corn soup when they go to a Chinese restaurant. If they are vegetarians, then it is plain sweet corn. If they fancy themselves as gourmets, then it’s sweet corn soup with crab meat. And if they are Punjabis, they order sweet corn soup with chicken.

The pattern at Thai restaurants is nearly as predictable. Almost everyone who goes to a Thai place orders the same soup: tom yum. This hot, sour and spicy soup is such a favourite that it also allows for many variations. Vegetarians can order the mushroom version. (Actually, vegetarians should not be ordering tom yum soup at all but we will come to that later.) Sophisticates can order the version with prawns, which is probably the most common expression of the soup. And yes, there is a chicken version for people who are not feeling particularly adventurous.

Tom yum is to Thai food what chicken curry is to India. Every region has its variations

But while it is tempting to talk about tom yum and sweet corn in the same breath, there is actually one important difference: tom yum is a real Thai soup. You will find delicious variations on the same basic theme in different parts of Thailand. It is also the most commonly ordered soup at Thai restaurants all over the world. In fact, the flavour of tom yum (‘chilli-lime’ in chef speak) has become a metaphor for the distinctive nature of Thai cuisine. You will find tom yum flavoured potato chips at many American grocery stores and tom yum flavoured peanuts make a great accompaniment to drinks.

The sweet corn soup we have in India, on the other hand, is not a real Chinese soup. Oh yes, there is a sweet corn soup in the south-west of China but it is not really anything like the version we get here. In fact, sweet corn soup as we know it is one of those made-up dishes (like American chop suey) that was created in the early part of the twentieth century when poor Chinese immigrants to the US opened little restaurants serving inexpensive meals. They used sweet corn – a new-world vegetable which is not native to China – because it cost very little and was easy to find in America. The taste of sweet corn was a familiar one for most Americans so it made Chinese food seem less alien to their palates.

When did sweet corn soup reach India and why did it become so popular? I have asked many of the old restaurateurs why they put it on their menus but have failed to get any satisfactory answers. All they will say is that it was always a restaurant dish, one the Chinese community in Calcutta or Bombay never really ate at home. My theory is that the first Chinese restaurants in India had very little to do with real Chinese cuisine. They simply followed the lead of American- Chinese restaurants. The American-Chinese had devised their own menus taking the principles of Cantonese cooking, throwing out most of the high-cost meats, simplifying the flavours and focusing on noodles, vegetables and rice because they were cheap and filling. (That accounts for the global popularity of chop suey, chow mein or fried rice).

Corn is not native to India either. But, even in the 1940s, it was easy enough to buy cans of sweet corn kernels. So Calcutta’s Chinese community probably improvised on the original American-Chinese recipe by making a simple soup out of canned corn. The point of the soup anyway, was that it had very little flavour. Guests were encouraged to add soy sauce, chilli sauce and even chopped green chillies in vinegar according to their own tastes. Part of the fun of ordering sweet corn soup was to get a thick golden broth at the table and to then, like some hungry Picasso, change the colour by adding black (soy sauce), red (chilli sauce) or whatever. When the soup was served with chicken or crab, all that the chef did was add a little pre-boiled shredded chicken breast or crab meat to the bowl of soup before it went out of the kitchen.

The American-Chinese devised their own menus taking the principles of Cantonese cooking, throwing out most of the high cost meats, simplifying the flavours and focusing on noodles (right), vegetables and rice (left). Also, Poor Chinese immigrants used sweet corn (middle) at their little restaurants because it cost very little and was easy to find in America.

The tom yum story is not so simple. It is to Thai food what chicken curry is to India. Every region has its own variations. The flavours can vary: in the north it is much spicier than elsewhere. So can the ingredients. In the south, near the Andaman Sea, it is common to put large prawns into the soup. And the herbs that are an integral part of the taste also vary from region to region depending on the local produce.

At any good Thai restaurant, they will make tom yum from scratch. The classic recipe requires you (skip this para if you are a strict vegetarian) to take the brains out of the prawns and to gently sauté them to give the soup its base. These days however partly for reasons of convenience and partly because of the yuck factor, most chefs just make a prawn stock. Once that’s done, they add the complex mixture of spices and herbs (garlic, makroot leaves, lemon grass, Thai galangal etc) that gives the soup its distinctive taste.

At many restaurants, however, they can’t be bothered to make the soup from scratch. Instead they fall back on ready made tom yum pastes or stock cubes. This may sound horrifying, but the truth is that even in Thailand more and more people are depending on store-bought pastes, masalas and cubes for their cooking. If they want classic Thai cuisine with freshly ground pastes then they go out to restaurants.

So there is nothing wrong with using a readymade paste or a cube. Speaking for myself, I make tom yum at home all the time. I use a readymade stock cube, but instead of adding water I add a light stock of fish or chicken made with cubes. Then I put in whatever I can find: stalks of lemon grass, garlic cloves, dried makroot leaves, mushrooms, galangal, prawns, chicken etc. The great thing about doing vegetable shopping in India these days is that all of these ingredients are readily available. They will probably cancel my Thai visa after they read this, but I find that even if you put unusual ingredients (chopped asparagus, baby corn, even sliced Chinese sausage!) the basic flavour of tom yum is so strong is that it works with everything.

Which leaves us with the vegetarian problem. In Thailand even those vegetarians who will not eat fish do not object if fish flavourings are used: fish stock, oyster sauce, fish sauce etc. Most Thai food does not get its saltiness from salt. Instead Thais prefer nam pla, a sauce made from fish which can be a little smelly on its own but is delicious when you add it to food. The problem is that nearly every readymade Thai paste or cube will have some nam pla in it. Vegetarians don’t always notice (but then they don’t notice that Worcester sauce is made with anchovies either and that every Bloody Mary is non-vegetarian by definition) but it is nearly impossible to find pre-packaged vegetarian Thai food.

I asked Ananda Solomon what he did at Thai Pavilion. Naturally, he makes all his own pastes from scratch and no cubes or packets are allowed into his kitchen. Ananda says that if you are a passionate cook then real tom yum is easy enough to make. As for vegetarians, he doesn’t see the problem. At Thai Pavilion they don’t use fish sauce for vegetarians but rely on soy. For his tom yum, he uses a vegetarian stock instead of the prawn stock that is normally part of the dish. I got Ananda to give me his tom yum recipe but I guess you can find similar recipes on the net. What you won’t find however is his secret vegetable stock recipe, which I finally prised out of him. Use it and you will never miss a meat or fish stock again when you make Asian food.

As for sweet corn soup, I won’t waste your time with a recipe. (How would it go anyway? “Open one can of sweet corn...). It is easy enough to order sweet corn soup from any takeaway. It is such a basic dish that whether you eat it at your neighbourhood Chinese dhaba or at the House of Ming, there won’t be much difference in quality. So if you like cooking, challenge yourself. Make a good tom yum instead!